Yes, it seems mat_postprocess_enable 0 only works with the VPK addon. VAAAAAAAAAAAAAAALVE!
+mat_hdr_level works on launch. in developer console: unknown command.
+mat_queue_mode works on launch and in developer console.
+mat_texture_list doesn't seem to work on launch. Probably works with a VPK addon. Uknown command in developer console.
This plugin could be fun
Edit: I've decompiled this vpk
https://steamcommunity.com/sharedfil.../?id=883184786 and it's a serious issue.
This basicly gives clients the opportunity to change any client convar that is locked and just recompile the vpk.